Noctilucent CloudsOur connection with NASA's AIM spacecraft has been restored! New images from AIM show that the southern season for noctilucent clouds (NLCs) is underway. Come back to this spot every day to see AIM's "daily daisy," which reveals the dance of electric-blue NLCs around the Antarctic Circle..

THE SOLAR WIND HAS ARRIVED: Earth is entering a stream of fast-moving solar wind that could spark bright auroras around the Arctic Circle this weekend. The gaseous material is flowing from a wide hole in the sun's atmosphere. NOAA forecasters say there is a 30% chance of geomagnetic storms on Feb. 17th and 18th. Free:Aurora Alerts

THE SUNSPOT IS LEAVING: Sunspot AR2699, which hurled a CME toward Earth and sparked brightpolarauroras on Feb. 15th, is about to vanish. The active region is rotating off the face of the sun this weekend. NASA's Solar Dynamics Observatory is monitoring the sunspot's magnetic canopy now seen in profile over the sun's western limb:

A sunspot's magnetic canopy is where solar flares happen. Magnetic lines of force criss, cross, and explode in a process known as "magnetic reconnection." Got a backard solar telescope? Keep an eye on the sun's western limb. With its canopy in full view, AR2699 might fire a parting shot worth photographing. Free:Aurora Alerts

A NEW DISTANCE RECORD FOR STARMAN: For the past week, astronomers around the world have been racing to set a very unlikely record: Who can take the most distant photo of a cherry red Tesla Roadster? At the moment, the record stands at 2.5 million km. Riccardo Furgoni and Giancarlo Favero set the mark on Feb. 15th when they used using a 0.8 m reflecting telescope at the Celado Astronomical Observatory in Italy to take these pictures:

"The object was only 16 degrees above our horizon shining feebly like a magnitude 19.3 star," they say.

Launched on Feb. 6, 2018, by a Falcon Heavy Rocket at Cape Canaveral, Elon Musk's Roadster is traveling around the sun on an elliptical orbit that will take it beyond the orbit of Mars. Every day it is getting farther from Earth. For comparison, 2.5 million km is about 6.5 times farther away than the Moon.

Other amateur astronomers around the world have also been photographing the distant electric car, piloted by a space-suited mannequin named "Starman." At the moment, Furgoni and Favero hold the distance record. But stay tuned, because records are meant to be broken!

The students of Earth to Sky Calculus flew a payload-full of these heart-shaped Venus pendants to the stratosphere onboard a high-altitude helium balloon. The one pictured above is floating 110,550 ft above the Sierra of Centrl California.

With a sterling silver backface that says "I Love You to the Moon and Back," these blue jewels make great Valentine's, Mother's Day, and birthday gifts. Each pendant comes with a greeting card showing the jewelry in flight and telling the story of its journey to the stratosphere and back again. Sales of this pendant support the Earth to Sky Calculus cosmic ray ballooning program and hands-on STEM research.

Every night, a network of NASA all-sky cameras scans the skies above the United States for meteoritic fireballs. Automated software maintained by NASA's Meteoroid Environment Office calculates their orbits, velocity, penetration depth in Earth's atmosphere and many other characteristics. Daily results are presented here on Spaceweather.com.

On Feb. 17, 2018, the network reported 6 fireballs.(6 sporadics)

In this diagram of the inner solar system, all of the fireball orbits intersect at a single point--Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). [Larger image] [movies]

Near Earth Asteroids

Potentially Hazardous Asteroids (PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time.

Notes: LD means "Lunar Distance." 1 LD = 384,401 km, the distance between Earth and the Moon. 1 LD also equals 0.00256 AU. MAG is the visual magnitude of the asteroid on the date of closest approach.

Cosmic Rays in the Atmosphere

Readers, thank you for your patience while we continue to develop this new section of Spaceweather.com. We've been working to streamline our data reduction, allowing us to post results from balloon flights much more rapidly, and we have developed a new data product, shown here:

This plot displays radiation measurements not only in the stratosphere, but also at aviation altitudes. Dose rates are expessed as multiples of sea level. For instance, we see that boarding a plane that flies at 25,000 feet exposes passengers to dose rates ~10x higher than sea level. At 40,000 feet, the multiplier is closer to 50x. These measurements are made by our usual cosmic ray payload as it passes through aviation altitudes en route to the stratosphere over California.

What is this all about? Approximately once a week, Spaceweather.com and the students of Earth to Sky Calculus fly space weather balloons to the stratosphere over California. These balloons are equipped with radiation sensors that detect cosmic rays, a surprisingly "down to Earth" form of space weather. Cosmic rays can seed clouds, trigger lightning, and penetrate commercial airplanes. Furthermore, there are studies ( #1, #2, #3, #4) linking cosmic rays with cardiac arrhythmias and sudden cardiac death in the general population. Our latest measurements show that cosmic rays are intensifying, with an increase of more than 13% since 2015:

Why are cosmic rays intensifying? The main reason is the sun. Solar storm clouds such as coronal mass ejections (CMEs) sweep aside cosmic rays when they pass by Earth. During Solar Maximum, CMEs are abundant and cosmic rays are held at bay. Now, however, the solar cycle is swinging toward Solar Minimum, allowing cosmic rays to return. Another reason could be the weakening of Earth's magnetic field, which helps protect us from deep-space radiation.

The data points in the graph above correspond to the peak of the Reneger-Pfotzer maximum, which lies about 67,000 feet above central California. When cosmic rays crash into Earth's atmosphere, they produce a spray of secondary particles that is most intense at the entrance to the stratosphere. Physicists Eric Reneger and Georg Pfotzer discovered the maximum using balloons in the 1930s and it is what we are measuring today.